This invention relates to material handling and storage systems, and storage mechanisms therefor. More particularly, this invention relates to multiple location storage rack structures and mechanisms for positioning loads in such structures.
Material handling and storage has been a progressively more sophisticated industry since shortly after World War II. Today, computer aided and automated storage and retrieval warehouses rise multiple stories. The Interlake Companies, Inc. has been a leader in the art of such warehouses. However, for a variety of reasons, most warehouses continue to involve the manual operation of fork lift trucks carrying loads on pallets.
In the art of such warehouses, strides have been made toward maximizing density of storage without sacrificing accessibility. In addition to standard, single load depth rack, The Interlake Companies, Inc. has designed both a drive-in rack and a gravity-flow rack and mechanism. The drive-in rack includes storage bays wide enough for fork lift trucks to drive into the bays. Loads are supported by rails along the sides of the bays, rather than shelf beams across the bays. The gravity-flow rack and mechanism includes beam supported rails which incorporate series of load supporting and conveying wheels. The rails are tilted, and smooth surfaced trays are placed under pallets, such that the palletized loads roll by gravity from their place of entry toward the opposite, and exit, side of the rack. The trays are placed under the pallets to eliminate obstruction of the system caused by the roughly constructed pallets failing to travel smoothly over the rail wheels.
For some applications, standard rack, drive-in rack, and gravity-flow rack all have disadvantages. The standard rack has the common disadvantage of waste of floor space for multiple aisles. Drive-in rack overcomes the disadvantage of waste of floor space, but reduces accessibility to loads. Drive-in rack is most suitable for storage of large volumes of loads such that all loads in a bay are identical. Accessibility to any one load is then not a concern. Gravity-flow rack requires storage trays, and each tray must be separately removed from the wheeled rails when its load is removed. The trays must then be returned to the place of load entry. Moreover, in a gravity flow rack, loads are loaded and removed from opposite sides of the rack rather than from a common side. The need to provide, remove and return storage trays, and the lack of a common side of loading and removal, are often disadvantages.